Ornithine decarboxylase activity, nucleic acids and cell turnover in the livers of pregnant rats

Abstract

SUMMARY1. Comparisons were made between the livers of pregnant and nonpregnant rats, all of which were fed on a ration of 20 g food per day.2. In the second half of pregnancy there were marked increases in the weight of the liver and in its total content of protein, RNA and DNA. RNA concentration increased from the 15th day of gestation.3. Between the 12th and 18th day of pregnancy liver weight, total RNA, total DNA and mean liver cell nuclear volume increased in parallel at approximately the same rate of 6-10 % per day.4. Ornithine decarboxylase activity was enhanced in pregnancy by the 5th day of gestation and rose to peak activity at the 18th day.5. The mitotic index of hepatic parenchymal cells was elevated in the first and last stages of pregnancy. The later peak in mitosis was associated with a rapid fall in mean nuclear volume.6. There was histological evidence of cell turnover in the liver of pregnant rats; enlargement of the liver was associated with both hyperplasia and cell deletion.

Protein metabolism in the mouse during pregnancy and lactation

“…The accelerated growth rate of the liver was maintained consistently over the whole period. Increases in the weight and protein content of the liver during pregnancy and lactation have been shown previously in rats (Chatwin et al, 1969;Campbell et al, 1974;Remesar et al, 1981;Mayel-Afshar & Grimble, 1982;Siebrits et al, 1985). The protein mass of the gastrointestinal tract also grew steadily throughout pregnancy and early lactation, but showed a particularly marked increase as lactation approached its peak at 15 days (Table 3).…”

Hepatic microsomal oxidative metabolism of pesticides and other xenobiotics in pregnant CD1 mice

“…Our observation that liver weight increases during pregnancy (Table 1) is consistent with that of other workers (2-4,23). The elevation in liver mass is generally attributed to the proliferation of parenchymal cells (24) and, indeed, we have observed that this enlargement is accompanied by an increase in total microsomal yield per liver. This is important when evaluating xenobiotic metabolism during pregnancy since this increase may represent a concomitant increase in the xenobiotic-metabolizing enzyme complements of the tissue.…”

The effects of folic acid supplementation during pregnancy in the rat

“…Several workers have shown that livers of pregnant rats show a progressive increase in weight, RNA, DNA and protein during gestation (Morgan & Winick, 1977;Campbell, Fell & Mackie, 1974;Naismith, 1966). However, the present study has demonstrated that Fola te supp lernen ta tion and pregnancy the feeding of excess folate to rats during pregnancy is associated with an additional increment in hepatic growth.…”